There are many reasons why a bone or limb may need to be lengthened, such as congenital bone disorders, disruptions in the bone's normal development, traumas, and many other medical problems. The resulting difference in the length of the limbs needs to be resolved in order to provide an acceptable level of quality of life for the patient.
Today, bone elongation is a common procedure in orthopedic medicine. The most realistic and the safest surgical options are based on the recently discovered phenomenon of “Callotasis”, or “bone distraction”.
In short, this means utilizing the natural healing process of the body that causes a bone that has been split in two to repair itself by creating new tissue to fill in the gap and heal the bone. In Callotasis, or bone distraction, the bone is progressively healed and lengthened by the slow distraction of the two split portions. At the end of the process, the new tissue consolidates into a perfect new bone.
Many related art devices, commonly referred to as “distractors”, utilize said bone distraction phenomenon to lengthen various bones.
Older, more common devices are external to the body and comprise, for example, sets of external rings, strings, and pins installed around the limb being treated and connected to the hone portions through the soft tissues. Such devices cause a large amount of pain and inconvenience to the patient. Additionally, such devices penetrate through the soft tissues, causing many septic problems and repetitive infections. Furthermore, these external devices are ungainly and greatly restrict the patient's ability to move about freely.
More recently, the related art has attempted to provide a solution to these problems by various means, proposing to implant devices within the medullar cavity of the bone (intramedullar). In order to extend the devices and cause the desired bone lengthening, a mover is required. Different movers have been proposed. Illustrative of such attempts include German patent No. 4002400, which relates to an intramedullar locking pin with a spring mechanism that is adjustable from outside; U.S. Pat. No. 5,074,882, which discloses a nail for gradually lengthening long bones, wherein the bone is lengthened post-operatively by rotation of a distal part of the limb with respect to the proximal part of the limb; US patent Application No. 2004030395, which features a surgical distraction for applying extending or tensioning force non-invasively to a patient's skeleton which relies on a magnetic actuating means located externally of the patient; and U.S. Pat. No. 5,961,553, which relates to a device for elongating long bones that includes an electric motor as means for moving the extension.
Because of the reliance of such devices on external sources of actuation, patients face a number of new drawbacks from use of such intramedullar devices. Intramedullar devices tend to have a high cost and limited elongation capabilities. Physicians face difficulties in managing the treatment programs that require patients to arrive at the medical facility. Furthermore, in addition to requiring the patient be at a specific location in order to actuate the lengthening process, the external actuation means itself may restrict the patient's mobility.
In addition, related art simply does not provide an inexpensive, effective solution that is comfortable for the patient and that provides an easily managed follow-up program, wherein the device is both completely internal and a completely mechanical device according to the principle of the present invention.